9514 1404 393
Answer:
168 square feet
Explanation:
The model has shading in groups of 10 where possible. This makes it relatively easy to find the partial products and add them up.
(10 +4)(10 +2) = 10·10 + 4·10 +10·2 + 4·2
= 100 +40 +20 +8
= 168 . . . . square feet